Algorithms and means analysis to reduce distortion in images and video signals
Students Name: Kazimirov Andrii Yaroslavovych
Qualification Level: magister
Speciality: System Programming
Institute: Institute of Computer Technologies, Automation and Metrology
Mode of Study: full
Academic Year: 2020-2021 н.р.
Language of Defence: ukrainian
Abstract: Kazimirov A.Y., Nakonechny R.A. (head). Algorithms and means analysis to reduce distortion in images and video signals. Master qualification work. - Lviv Polytechnic National University, Lviv, 2020. Extended annotation. By one definition, image quality can be represented by the level of accuracy at which different imaging systems capture, process, store, compress, transmit, and display the image-forming signals [1]. However, according to another definition, image quality is a certain combination of all visually significant attributes of the image [2]. And the difference between these definitions is that the first focuses on the characteristics of signal processing in different visualization systems, and the second - on the estimates of perception, which make the image suitable for observers. The image formation process is affected by some distortion that occurs between the moment when the signals pass to the capture surface and reach it, and the device in which the signals are displayed. Although optical deviations can cause significant image quality distortions, they are not part of the image quality assessment field [3]. For example, a digital image is formed by electromagnetic radiation or other waves as they pass through or are reflected from objects. Then this information is recorded and converted into digital signals by the image sensor [4]. Images are compressed, transmitted, captured and stored in different digital formats with different types and number of side artifacts. While speckle noise and coding artifacts are most common in biomedical programs, digital coding and transmission artifacts are considered dominant in entertainment and engineering applications [5]. The elimination of such distortions and noises is insufficiently studied and needs further study. The object of research - the processes of conversion and processing of image signals. The subject of research – methods and means of improving the quality of image and video signals. The purpose of the study: the purpose of this master’s thesis is to study the methods of eliminating distortion in images and video signals. To achieve this goal, the following tasks were performed: the analysis of existing algorithms for eliminating distortions in the images, the main areas of improvement of these algorithms and their comparison based on testing. Research results: as a result of the research performed in this work, software was developed that demonstrates the comparison of different combinations of wavelet transforms and thresholding methods to reduce image noise. The structure, advantages and disadvantages of the most common algorithms and means of reducing distortion are also considered. Keywords - image and video signals, wavelet transform, thresholding methods, distortion elimination. List of used literature sources: Burningham, Norman; Pizlo, Zygmunt; Allebach, Jan P. (2002). Image Quality Metrics. Encyclopedia of imaging science and technology, 598. Wang, Zhou; Bovik, Alan C. (2006). Modern image quality assessment, 34 – 35. Sheikh, Hamid Rahim; Bovik, Alan C. (2006). Image Information and Visual Quality. Transactions on Image Processing, 432 – 434. William K. Pratt. (2007). Digital Image Processing: PIKS Scientific Inside, 121 – 123.